Impostor syndrome (IS) is a personal belief that you do not deserve or did not work hard enough for your accomplishments. Those with IS often believe that their success is not due to their own dedication and skill, but instead, luck or happenstance. This phenomenon has recently shown a prevalence in higher education academic populations, but because IS research has just begun to pick up consistent traction in the last decade, there are still many gaps in the literature. Through a one-time questionnaire, this study aimed to build upon existing research and fill existing gaps in a basic sciences academic sample. Within this study, PhD students, post-doctoral fellows, and academic faculty members were studied to establish the presence and severity of IS. This study aimed to build upon existing literature and further identify personal and academic factors that related to IS within each sample. Additionally, this study aimed to address the relationship between career and academic milestones and progression and IS. The questionnaire ranged from 36-42 items, 20 of which being the 20-item Clance Impostor Phenomenon Scale. At the time of data analysis, there were 249 qualifying participants, consisting of 163 PhD students, 16 post-doctoral fellows, and 70 academic faculty members studying and/or employed across seven basic sciences disciplines. This study found that 97.5% of PhD students, 93.8% of post-doctoral fellows, and 85.7% of academic faculty members had some level of IS. The PhD student participants had the most heightened IS, with over 80% of them having either high or intense IS feelings. Post-doctoral fellows had the next highest IS, with just over half of the post-doctoral sample having either high or intense IS. Contrastingly, only 38.3% of academic faculty respondents had either high or intense IS. When observing the total sample, those who reported a female gender identity averaged higher total IS scores. Multiple factors were found to relate to IS, and these differed for each sample. For PhD students, the presence of a CDD, an uncomfortable school/workplace environment, and the highest degree held were significant to IS measures, and they all related to increased IS. Post-doctoral fellows had higher IS in fellowship years two and three and White or Caucasian fellows had significantly higher IS in relation to Asian or Pacific Islander participants. The post-doctoral sample had many factors show practical significance, with providing mentorship to students and having presented at a conference relating to higher IS. The academic faculty sample showed that receiving a promotion and having received academic awards significantly related to lower IS. Practical significance was found as well, with the milestones of providing mentorship to students and receiving academic rewards showing relation to higher IS scores. Individually, all three samples showed either statistical and/or practical significance between contemplations of quitting academia and total IS scores, with those who have contemplated quitting academia averaging higher scores. These results show a high prevalence of IS within this basic sciences sample, with the most severe IS observed in PhD students. There were many differences in results between samples. Ultimately, the factors that showed a relation to IS measures in this basic sciences sample should be further studied so that meaningful and effective IS prevention, coping, and management strategies can be created and tested, because there are currently few suggestions. Furthermore, longitudinal studies would be largely beneficial for IS research, as most existing studies are currently cross-sectional in design. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]